Blade dicing, which mechanically cuts a wafer by a rotating blade, is generally used for singulation of a semiconductor substrate into chips. In the blade dicing, a plurality of dicing grooves are successively formed on the semiconductor substrate so as to singulate the semiconductor substrate into chips. Thus, in the blade dicing, if the chip size is reduced and the number of dicing grooves (the number of lines) is increased, there arises such a problem that the dicing time becomes longer in proportion to the number of lines.
In addition, a chip obtained by blade dicing has right-angled corner portions, and has a low shock resistance. Furthermore, in the blade dicing, since fine cracking (chipping) occurs at an end portion of the chip, the chip obtained by blade dicing has a low flexural strength.
Incidentally, in recent years, it has been proposed to form a deep hole with a high aspect ratio in a single-crystal substrate by a chemical action.